Police continue to investigate whether fatigue or another factor was the cause of a single-car crash that killed three people including a young boy near Ulladulla on Saturday morning.
Emergency services were called to the Princes Highway at Lake Tabourie, about 13km south of Ulladulla, about 4.30am to reports a Honda Accord travelling north left the road and hit a tree.
A 43-year-old woman from Narooma, her 47-year-old male passenger and a five-year-old boy, both from Bodalla, were killed in the crash.
A 46-year-old male passenger from Dalmeny was airlifted to Canberra Hospital where he remains in a critical condition in an induced coma on Sunday afternoon.
Nearby residents attempted to help the driver and passengers but they tragically died at the scene.
South Coast police spent hours on Saturday investigating the scene to try to determine what led to the fatal crash after the group reportedly left from Narooma bound for the Central Coast.
South Coast Police District Greg Moore told the media "we don't have a firm indication of what caused the crash at this point but certainly can't rule out factors including fatigue".
There were significant traffic delays as only one lane of the highway was open under stop/slow traffic control near Weymouth Road.
All lanes were reopened shortly before 12pm after the site was cleared.
A report will be prepared for the Coroner.
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